154. Parmelia] 39. PARMELIACEAE 323 



A. Thallus olivaceous, brown or darker 



B. With coralloid branchlets or soredia above 

 C. Lobes broad 



D. Bearing scattered warts or coralloid branchlets 



on the thallus and exciple 49. P.aspidota 



D. Bearing powdery soredia on the thallus, 



especially toward the margins SO. P. conspurcata 



C. Lobes narrow 



D. Lobes variously branched and imbricated, sometimes 

 bearing coralloid branchlets or soredia 



E. Lobes smooth and often shiny; spores 8-15 X 7-9 n . 52. P. omphalodes 

 E. Lobes becoming wrinkled; spores 8-11 X 5-7 m . . . 53. P. prolixa 

 D. Lobes digitately much-branched, usually thickly 



covered with whitish or greenish gray soredia . . . . 51. P. sorediata 

 B. Without coralloid branchlets or soredia above 

 C. Lobes broad 



D. Spores constantly 8 in each ascus 



E. On rocks; lobes wavy and radiately folded .... 55. P. glabra 

 E. On trees; lobes branched and sometimes imbricated . 56. P. olivacea 



D. Spores 16-24 or more in each ascus 54. P. multispora 



C. Lobes narrow, palmately much-branched 57. P. stygia 



1. Parmelia rudecta Ach., Syn. Meth. Lich. 197. 1814. 

 P. Borreri var. rudecta (Ach.) Tuck. 



Thallus middle-sized to large, rather closely adnate, greenish gray to ashy, 

 commonly wrinkled, bearing many granules or coralloid branchlets, the lobes wide 

 and short, somewhat branched, the margins entire to cut-crenate, and rarely white- 

 powdery; ashy to pale brown below with white or darkening rhizoids; apothecia 

 rare, small, 3-5 mm. across, subsessile, the disk deeply concave, chestnut-brown, the 

 exciple entire, crenulate, or irregular; spores ellipsoid, 10-16 X 6-8.5^.. 



On trees and rarely on rocks, throughout the United States. 



2. Parmelia Borreri Turn., in J. E. Smith & Sowerby, Engl. Bot. 25:1780. 1807. 

 P. Borreri var. hypomela Tuck. P. Bolliana Mull. Arg. 



Thallus middle-sized or larger, usually wrinkled, rather closely adnate, greenish 

 gray or varying toward ashy or brownish, sometimes covered more or less by 

 round soredia, the lobes rather wide and short, more or less branched, with usually 

 cut-crenate margins; ashy to pale brownish, or very rarely blackening below, with 

 white or darkening rhizoids; apothecia middle-sized to large, 3-14 mm. across, 

 subsessile, the disk concave to deeply concave, chestnut-brown, the exciple entire 

 to crenate or irregular; spores ellipsoid, 9-18 X 6-8 /x. 



On trees and rarely on rocks, widely distributed, eastern United States. 



3. Parmelia lanata (L.) Wallr., in Bluff & Fing., Comp. Fl. Germ. 1:529. 1831. 

 Lichen lamttis L., Sp. PI. 1155. 1753. P.pubescens (L.) Vainio. P. stygia var. 



lanata (L.) E. Fries. 



Thallus small, usually subfruticose and procumbent, blackening, the lobes 

 narrow and round, subdichotomously much-branched, the branches usually en- 

 tangled; usually lighter colored below and without rhizoids; apothecia middle-sized, 

 2-6 mm. across, the disk flat to convex, chestnut-brown and darker, the exciple 

 subgranulate; spores round to ellipsoid, 5-12 X 3-7 /x. 



On rocks, California and Wyoming. 



4. Parmelia cubensis Nyl., Flora 68:611. 1885. 



Thallus middle-sized, adnate, grayish white, smooth to more or less roughened, 

 the lobes short and wide, or becoming somewhat elongated and obscurely branched, 

 sometimes imbricated, the margins wavy to incised-crenate; dirty olivaceous below, 

 with pale rhizoids; apothecia small, 1-2.5 mm. across, the disk concave, chestnut- 

 brown, the exciple entire; spores ovoid-ellipsoid, 9-12 X 7-8.5 fi. 



On trees, Louisiana and Florida. (Nylander states that this species is near 

 Parmelia texana but not sorediate.) 



